1. Field of Invention
The present invention generally relates to the field of food and beverage containers. More specifically the present invention relates to a self-cooling container apparatus containing a beverage or other food product and to methods of assembling and operating the apparatus. The terms "beverage," "food," "food products" and "container contents" are considered as equivalent for the purposes of this application and used interchangeably.
For the first several preferred embodiments, the apparatus includes a container such as a metal or plastic can containing a product and having a conventional unified bottom and side container wall terminating in an upper sealing flange referred to hereinafter as a container rim. A refrigerant receptacle is provided including a receptacle cup having a cup wall. The cup wall having an expandable portion sealingly connected to a top wall to form a refrigerant receptacle chamber. A portion of the top wall shaped into an invertible conical reservoir for temporary storage of liquified refrigerant; the reservoir having a small port opening or a semipermeable membrane, at the lowest point for transfer of liquified refrigerant into and out of the refrigerant chamber, hereinafter referred to as the refrigerant port. Several cup wall sections extend vertically above the top wall to connect to a sealing flange which extends laterally, hereinafter referred to as a receptacle rim. The spaces between the cup wall sections act as passageways for product and hereinafter referred to as product passageways. The receptacle is filled with a solid or powdered form of carbon molecules of Fullerene nanotubes (C.sub.n,n&gt;1,000,000), or alternatively, an expanded metal sponge is encased within the receptacle. The terms Fullerene nanotubes, expanded metal sponge are considered equivalent for the purposes of this application and used interchangeably. A conventional beverage can lid is further provided, including a lid panel with a lid opener mechanism and a lid lateral edge.
A method of apparatus assembly is provided including the steps of filling the receptacle with Fullerene nanotubes or an expanded metal sponge; lowering the receptacle through the container rim and resting the receptacle rim on top of the container rim; filling the reservoir formed on the top surface of the receptacle with liquified refrigerant; transporting the container and filled receptacle to the product filling machinery, during which period the liquified refrigerant fills the Fullerene nanotubes inside the receptacle through the refrigerant port; filling the container with product so that a substantial amount of the receptacle's surface area is immersed in the product; placing the lid on top of the receptacle so that the lid lateral edge rests on the receptacle rim; and seaming the lid lateral edge and receptacle rim onto the container rim using conventional beverage and food container seamers. After seaming, the refrigerant is warmed to ambient temperature, whereupon it partially evaporates and develops internal pressure against the receptacle wall and evaporating gas exits from the receptacle through the refrigerant port into the container until the pressure within the container equals the pressure within the receptacle, whereupon evaporation stops.
A method of operation is provided in which the consumer operates the lid opener mechanism to open the lid and thereby releases vaporized refrigerant from the receptacle and the container. The pressure within the receptacle becomes greater than the pressure outside the receptacle, and the reservoir is forced by the pressure inside the receptacle to invert into a dome so that the refrigerant port is now located above the product level and the gas exits therefrom to the atmosphere. The remaining liquid refrigerant progressively boils into a vapor state and escapes from the Fullerene nanotubes, through the refrigerant port, and through the container opening, drawing heat out of the food or beverage through receptacle walls. Once all the refrigerant has been released, the consumer can consume the product.
As an alternative to the cup with an expandable wall, the apparatus includes a container such as a can containing a product, a secondary receptacle placed inside and at the bottom of said container having a unified bottom wall, side wall, and a top wall forming a refrigerant receptacle and providing a broad surface area for heat transfer and having at least 80 percent of its volume filled with carbon Fullerene nanotubes and a liquified refrigerant such as carbon dioxide or nitrogen. A small vertical tube member projects from the receptacle and terminates above the product level. The tube member terminates above the product level with a refrigerant port. A conventional beverage can lid is further provided, including a lid panel with a lid opener mechanism and a lid lateral edge.
An alternative method of apparatus assembly is provided including the steps of filling the receptacle with Fullerene nanotubes or alternatively, encasing an expanded metal sponge in the receptacle; charging the receptacle with a liquified refrigerant through the refrigerant port; lowering the receptacle into the container so that the receptacle rests at the bottom of the container; placing the lid on top of the container, so that the lid lateral edge rests on the container rim; filling the container with product so that a substantial amount or all of the receptacle's surface area is immersed in the product, and seaming the lid lateral edge unto the container rim using conventional beverage and food container seamer machinery. After seaming the lid and the container, the refrigerant is warmed to ambient temperature, whereupon it partially evaporates and develops internal pressure against the receptacle wall, and gas exits from the receptacle into the container through the refrigerant port at the end of a vertical tube above the product level until the pressure within the container equals the pressure within the receptacle. The evaporation stops thereafter.
A method of operation is provided in which the consumer operates the lid opener mechanism to open the lid and thereby releases vaporized refrigerant from the receptacle. The remaining liquid refrigerant progressively boils into a vapor state and escapes from the Fullerene nanotubes, through the receptacle port, and through the container opening, drawing heat out of the food or beverage through receptacle walls. Once all the refrigerant has been released, the consumer can consume the product.
2. Description of the Prior Art
The use of high pressure refrigerants such as carbon dioxide and nitrogen for self-cooling beverage containers has been known for some time now. However, due to the high containment pressure of the liquified form of these gases, very strong and thick-walled containers are needed to store enough quantities to cool a conventional beverage container. The use of low pressure gases, such as HFCs and CFCs have resulted in a greater and urgent need for more environmentally benign gases, such as carbon dioxide and nitrogen, since these gases can be recovered and recycled from the atmosphere without a change in the net balance of global warming gases or ozone depleting gases. Also, the cost of the lower pressure gases is far higher than the cryogenic gases such as carbon dioxide and nitrogen, and the thermodynamic properties of the latter are far more suitable for the purposes of cooling the contents of a beverage or food container. Another good reason why the higher pressure gases are more suitable for this application, is that they present very little or no health hazards to the consumer, and in fact can be in direct contact with the food or beverage product without creating any adverse effects for the consumer.
The natural structure of most fibrous fruits and vegetables is amazingly useful and elegant for storing pressurized liquids such as water, fructose, glucose, acetic acids, citric acids etc. Most naturally occurring containers such as apples and oranges, consist of sponge-like fibrous interiors holding the liquid in place with an economy in skin thickness unprecedented in engineering design.
Changes in natural temperature can exert tremendous pressures on the skin of the fruit without any evident damage. This is due to the ingenious method of containing this pressure. This example from nature, relies on distribution of the pressure to smaller fibrous compartments each of which can hold a much greater pressure due to its smaller surface area. While the entire surface area for heat exchange is maximized by these multitudes of tiny compartments, the pressure and stress retention properties have been enhanced considerably.
Recent developments have shown that the element carbon can be made into tiny compartmentalized tubes called Fullerene nanotubes. These tubes can hold pressurized refrigerants such as nitrogen and carbon dioxide with incredible efficiencies even at room temperature.
While previous attempts to use carbon matrices to store refrigerants have been successful, the efficiency has been too low for applications such as the present invention. Thus, the potential use of simple carbon matrices for self-cooling beverage containers is limited in scope and efficiency. Firstly, a back pressure of some 200 pounds per square inch (200 psi) is needed to force the matrix to absorb the refrigerant at an efficiency of about 10 percent concentration by volume.
Fullerene nanotubes can be manufactured in different diameters and lengths. This fact allows the present invention to effectively use this property to design Fullerene nanotubes that will store various gases without the need for any back pressure even at room temperature.
By designing the Fullerene nanotubes to store the refrigerant for the present invention at a pressure slightly higher than atmospheric pressure, the refrigerant could be stored under stable conditions in a receptacle of nominal wall thickness, such as in a plastic membrane containing the Fullerene nanotubes. Further the refrigerant such as carbon dioxide could advantageously be in direct communication with the contents of the container thereby eliminating the need for expensive valving. This combination of parameters can be used to manufacture an environmentally friendly, cost effective and commercially feasible self-cooling container.
It is thus an object of the present invention to provide a simple and cost-effective apparatus for cooling the contents of a container which uses Fullerene nanotubes to store high pressure inert gases for cooling a beverage or food product at room temperature.
It is another object of the present invention to provide such an apparatus with no complicated valving.
It is a further object of this invention to provide for an apparatus containing a high pressure liquified refrigerant such as carbon dioxide in a thin walled and inexpensive container, and to expose the beverage or food product to be cooled to a maximum surface area for rapid and efficient thermodynamic heat transfer.
It is another object of this invention to provide an apparatus in which a smaller volume of cold refrigerant is exposed to a larger heat transfer surface area such as by corrugating the refrigerant receptacle wall, to increase the evaporation rate of the liquified refrigerant.
It is still another object of the present invention to provide a self-cooling container apparatus containing a refrigerant receptacle filled with Fullerene nanotubes with either expandable or narrowly spaced apart walls for rapid and efficient transfer of heat out of the container contents.
It is still another object of this invention to provide such an apparatus which both releases refrigerants above the level of the container contents and opens a passage for the container contents to be consumed with a single action by the consumer.
It is still another object of this invention to provide such an apparatus containing a refrigerant receptacle filled with Fullerene nanotubes or an expanded metal sponge, with expandable walls that respond to pressure changes within and without the receptacle walls so that the receptacle walls will be stress-free during its operation.
It is also another object of this invention to provide such an apparatus with a reservoir into which liquified refrigerant can be easily poured during charging, so that the refrigerant can easily flow through a port in the reservoir into the Fullerene nanotubes for storage and to advantageously provide this means of charging the receptacle with refrigerant during manufacture of the apparatus without slowing the typical beverage bottling process.
It is finally an object of the present invention to provide such an apparatus which cools the contents of a container without any changes to the manufacturing processes of a conventional beverage container.